• General Motors goes to trial today in the first cases over deadly defective ignition switches in its vehicles. The trials could help G.M. and lawyers for the plaintiffs work out trial strategies or help determine whether to settle.

• The drug maker Shire agreed to buy Baxalta today in a deal valued at about $31 billion. The combination would create a giant in the treatment of rare diseases.

You won’t catch her in your class, though. She arranges for private sessions with friends, aides and sometimes her daughters.

BACK STORY

How’s that resolution going? A study shows that two out of five people who start a diet for the New Year break it in the first week.

With all the attention on diets, past and present, we looked at what our ancestors ate.

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Two out of five people who start a diet for the New Year break it in the first week.Credit
Malin Fezehai for The New York Times

About 100 million years ago, tree-dwelling apes believed to be our ancestors were for the most part vegetarians, scientists say, eating berries, seeds, nuts, grasses and fruits — as well as insects and the occasional small creature.

It wasn’t until roughly three million years ago that our more recent ancestors are thought to have started eating meat regularly.

Various theories account for the growth in brain size in the first Homo species, about two million years ago. Some scholars say it was a meat-rich diet that led the first Homo species to make tools.

Those tools helped draw out extra nutrients from cooking animals and plants, and led to biological and evolutionary changes that made us who we are today.

The beverage of choice was water from lakes, ponds or streams. Fermentation was discovered only about 10,000 years ago, so alcohol came relatively recently. Even more recent was the habit of drinking cow milk, an innovation of Northern Europeans.